Cataracts develop as part of the aging process, so everyone is at risk eventually. According to a recent article from the American Academy of Ophthalmology, the risk factors include:

Advanced age;
Diabetes;
A family history of cataracts;
Extensive exposure to sunlight;
Smoking;
Obesity;
High blood pressure;
Previous eye injury or inflammation (swelling) in the eye;
Previous eye surgery;
Long-term use of steroid medication (especially combined use of oral and inhaled steroids).

If you have any of these risk factors, and your vision is not as clear as it once was, then you may be developing cataracts. Visit your local optometrist as the first port of call for an eye health check and refraction.

Cataracts are readily treatable with a local anaesthetic operation. Multi-focal implants are also available to restore both distance and near vision, reducing or eliminating your dependence on all glasses.

Kate asked:

Hi,

I’ve been to consults at two clinics, one that does PRK, and the other LASIK (with a blade). Both clinics offered a similar quote and both said I was an ideal candidate for the surgery (I’m a healthy 23 year old female with mild astigmatism and the same prescription of -1.5 in both eyes since I’ve had glasses (2001). The only thing a out of the norm is that my corneas are a little steep (46). Is there going to be a benefit to me choosing one surgery over the other?

Cheers, Kate

Winston asked:

I am 19 , with -6.25 in the left eye and -7.25 in right. I have been wearing glasses for about 9 to 10 ten years.
What would you recommend? I do boxing as well as other physical activity.

Omar asked:

Good Afternoon Mr Allamby,
I’m considering getting some treatment on my eyes, but am very worried about the long-term effect cutting the cornea can have. As i get older and my eyesight deterioates. will the my eyesight be worse off than if i had just kept wearing glasses?

Omar, I think this is one of the most common worries that prospective candidates have when considering laser eye surgery be it LASIK or PRK. It is just over 20 years since we first performed PRK for short-sight, and just under 20 years for LASIK, so we have considerable experience of long-term results.

The long-term outcomes have been excellent to date. Regression is seen in the London PRK study in 1-2% of patients, with a partial return to myopia, but not as bad as the vision had been before without glasses.

Cutting the cornea (e.g. to create a flap or flap disc) has been around for decades. Lamellar cuts were made in the 50s, and the first mechanical keratome was first used in 1963. No long term problems were seen, except when too little thickness was left in the cornea. At my clinic, we use a high safety standard of leaving 300 microns in the corneal bed, after creating the flap with a femtosecond laser and using the excimer laser to reshape the cornea.

The main worry is in excessive weakening of the cornea. However, the incidence of bending of the cornea through weakness in post-LASIK patients is the same as the incidence of bending from a disease known as keratoconus (KC). So in normal LASIK where all the safety parameters are observed, we are not sure if LASIK actually contributes to corneal bending post-operatively.

The key here, as always, is rigorous screening pre-operatively and visiting a centre where you get sufficient time for your consultation. Some clinics do consultations in 30 minutes, or even less. Others (mine included) spend much longer. Focus consultations take at least 2 hours.

Choose carefully.

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Faisal asked:
I am short sighted, wearing glasses for almost 15 years. Just wanted to know whether I am a suitable candidate for laser eye surgery or not. Thanks

Faisal,
Being short sighted and wearing glasses for many years is typical. You will need a full consultation to determine if you are suitable for laser eye surgery. Some of the main factors will be the scans of your corneas, prescription, corneal thickness, and eye examination.

For LASIK laser eye surgery safety, there are 3 things you must look for when you plan to go ahead. This LASIK safety trio means a more accurate result and the safest procedure we know of today:

1. Choose a blade-free all laser LASIK technique – using the latest femtosecond lasers means no blade is used in the surgery. Check with any clinic you talk to that they can offer blade-free LASIK – if they can’t then they are out of date and should be avoided.
2. Wavefront-based LASIK is a must today, so make sure you go for that option. For example, at FOCUS Laser Vision we only do wavefront treatments so that is taken care of. At other centres such as Optical Express, do not choose their non-wavefront option.
3. Get the safety and reassurance of NHS consultant corneal specialist surgeons to do your treatment – the three laser eye chains do not offer this for the great majority of their treatments. Premier centres like Moorfields Eye Hospital, Centre for Sight and FOCUS Laser Vision do.

This is a common question about laser eye surgery safety I get asked by patients:

What happens if my vision isn’t right after treatment?

Most people don’t realise that the effect of laser eye surgery, including LASIK, LASEK and PRK procedures, CAN be fully reversed.

Although this isn’t necessary because if the prescription for glasses hasn’t been fully corrected then a second treatment is easily performed to fix that and stay free from the need for glasses or contact lenses. If the effect of the laser correction is a bit too strong or too weak, we call this an over-correction or an under-correction respectively.

All over- and under-corrections can be treated easily. In fact, as I mentioned, the whole laser eye treatment can be reversed. The move over to the Ziemer blade free system (Z-LASIK) has dramatically reduced the need to re-do LASIK treatments.

Most clinics quote enhancement rates of around 5%.  BUT with Z-LASIK for short-sight I have only had to adjust one case in the last 200, so that’s a 0.5% rate. Without any hype or spin, that’s just very impressive and a great step forward.

To fully reverse the effect of e.g. a short-sighted laser eye treatment, we remove some tissue from the outer part of the cornea to put the corneal curvature back to where it started. So now an equal amount of tissue has been removed across the cornea and so the focus would be back where it started. Of course, the cornea is a little thinner than before, but still strong enough for its role.

It’s the accuracy of the dual laser approach that allows such a very low enhancement rate, which means 99.5% of short-sighted patients are on target and very happy with only one treatment and without the need for a top-up.

IMPORTANT NEWS for those people considering having LASIK laser eye surgery.

There appears to be a fundamental difference between LASIK flaps cut either with a blade or created with a laser. Laser created flaps mean a safer surgery as the results are more accurate, so fewer enhancements needed, and the eye is left stronger.

Making a replaceable flap is the first part of the LASIK procedure, just prior to reshaping the cornea to correct vision. Until recently (and still in many clinics) the flap was made by a physical cut with a very sharp razor blade contained within a precision device. However several clinics and the major three chain operators have invested in femtosecond lasers to create the corneal flap without the need for a blade.

This is known as blade-free LASIK, dual laser LASIK, Z-LASIK or IntraLASIK depending on which clinic you are talking to.

We know that thicker flaps cut with a blade do not fully heal and can be lifted up surgically even many years later. Traditional blade flaps are thicker and cut deeper into the cornea. However laser flaps are thinner and leave the eye stronger afterwards.

However a key difference highlighted by Professor John Marshall in London is that because these very thin laser flaps pass through near the surface of the cornea where the collagen is different from deeper down, they actually heal down and are not able to be lifted later on. This means the eye regains strength again with a laser flap, but not with a blade flap.

Newer blade machines have been introduced in 2008 and 2009 that cut thinner flaps to compete with the thin femtosecond laser flaps which should benefit from the better healing seen in sub-120 micron flaps

My recommendation to you when choosing a clinic is to be able to select to have a femtosecond laser procedure at a clinic that has that technology. They are more expensive than blade procedures (expect to pay around £300 more per eye) but well worth the likelihood of a long-term increase in safety.

THIS is a question I often get asked. It’s a very good question.

Preview post…

Some new research from Professor John Marshall has helped shed light on this key topic and is something that everyone who is thinking about LASIK laser eye surgery needs to know.

Check back next week for my post on this topic…

The new femtosecond lasers have eliminated the need for a blade in LASIK laser eye surgery. All leading laser eye treatment clinics now offer blade free LASIK as a safer and more accurate procedure for patients.

Traditional LASIK has used a microkeratome to cut a flap. The microkeratome is a hand-held device, which contains a steel blade that moves back and forth to create a cut as it travels across the cornea. A microkeratome is only capable of making a single, one-dimensional cut across the cornea. As it cuts, the blade oscillates back and forth, which can leave an irregular surface after the flap is lifted. This can affect the quality of your postoperative vision.

One week after surgery more than 76 percent of femtosecond laser patients achieved an uncorrected visual acuity of at least 20/16 (better than 20/20) compared to only 58 percent of microkeratome patients

Because of the unique way in which the All Laser Method (femtosecond laser) creates a precisely positioned layer of micro-bubbles just beneath the surface of your eye, it creates a smooth even surface after your flap is lifted. With this method, a blade never touches your eye.

[youtube]http://uk.youtube.com/watch?v=spJHR3FJvTg&locale=en_GB&persist_locale=1[/youtube]

Tags: LASIK

Let’s look at the second of Carlo’s questions on laser eye surgery:

My name is Carlo and I have recently discovered this great blog. I would like to ask a couple of questions regarding eye surgery:
Question: Is it true that the LASIK procedure has not been approved for air-force pilots and astronauts in the US but PRK and LASEK has?

No, this is not true.

LASIK was approved for use on consumers a decade ago and reportedly more than 11 million LASIK procedures have been performed in the US. This means LASIK laser eye surgery is the most-common American elective surgical procedure.

NASA has approved LASIK for use on pilots, mission and payload specialists who face extreme and often physically demanding conditions in space. The all-laser LASIK technologies, using a blade free femtosecond laser approach, have also been cleared for U.S. military personnel, including most recently Air Force pilots.

“NASA’s approval is further evidence that today’s LASIK exceeds all established standards of safety and effectiveness,” said Steven Schallhorn, M.D., retired captain of the U.S. Navy.

Though LASIK has been around for a long time, concerns about the harsh environment in aviation prevented its use. To date, aero-medical professionals have been cautious of employing the procedure on military pilots who often encounter environmental extremes such as high altitude, dry air, wind exposure and “G” forces. In space, other conditions further add even higher levels of concern due to the very high level of precision needed during flight and space walks.

Defense Department’s research into laser vision correction included the following results:

# In a study of different methods to create the LASIK flap, 370 naval personnel underwent bilateral (both eyes) wavefront-guided LASIK with either the femtosecond laser (blade free) or microkeratome blade. One week after surgery more than 76 percent of femtosecond laser patients achieved an uncorrected visual acuity of at least 20/16 (better than 20/20) compared to only 58 percent of microkeratome patients

# In an evaluation of 785 pilots, 89% of Navy aviators evaluated their ability to land on an aircraft carrier as moderately to significantly better after laser eye surgery. None said it was worse after treatment

# A separate study determined that over 90 percent of marksmen had improvement in marksmanship skills after laser eye surgery; an impressive finding given the visual precision of marksmen

LASIK, particularly blade free femtosecond LASIK, appears to have established itself as a very effective and reliable procedure. The move from blade to laser blade free has allowed another significant improvement in results (now targeting better than 20/20 as a standard of care) according to the above research findings.

I recently received this email with a couple of great questions:

My name is Carlo and I have recently discovered this great blog. I would like to ask a couple of questions regarding eye surgery:

a) Can the creation of a flap in the eye potentially lead to problems? Should PRK and LASEK be better in the long run for patients?
b) Is it true that the LASIK procedure has not been approved for air-force pilots and astronauts in the US but PRK and LASEK has?

There is a lot of confusion on the web about those issues. Could you spend some time clarifying that?

Let’s look at the first question now and I will address the second in a subsequent posting.
The majority of surgeons use the LASIK technique, where a thin flap is created in the top part of the cornea before applying the vision correction laser. More than 90% of laser eye surgery procedures are LASIK rather than surface laser treatments (PRK or LASEK).

There has not been any research to show signifiant differences in results between LASIK and PRK for short sight so whichever you choose to have, the final outcome will be the same. However, for long sight or reading vision correction, LASIK appears to give a more stable results and this is my preferred method for these types of prescription.

But let’s stay with short sight for the moment, where the vision and stability are not affected by the choice of procedure. It then comes down to safety. I personally used to prefer PRK over LASIK due to the small but measurable complications arising from using a blade to cut a flap. At that time, when I asked myself which procedure I would have, it would have been PRK.

However, with the arrival of the very safe and predictable laser flap makers (femtosecond lasers) I no longer subscribe to that view and would personally now choose to have all-laser LASIK. The femtosecond lasers create a very predictable and thin flap time after time, with greater precision and safety than the mechanical keratomes could. Early research also shows improved vision results, especially in reaching the very high target of better than 20/20 vision.

You still need an expert surgeon and a very thorough examination and consultation because there are points we can detect which do predict a bigger chance of having a problem in the long term. Such patients need to be screened out of the LASIK or PRK process and should not have surgery.

So choose an expert centre with an expert surgeon and you will have a safe and predictable experience and result. You can comfortably opt for LASIK over PRK/LASEK without worries for the long term.

Certainly, patients much prefer LASIK as vision is very good within a few hours (even quicker with our Z-LASIK approach) and they can be back at work the next day, rather than needing to take several days off work. Also, most patients find PRK or LASEK to be a pretty painful experience for 2-3 days after correction (the procedure itself is painless).

I get asked about the so-called ‘femtosecond‘ lasers now being used in LASIK laser eye surgery, and what these devices do. OK, here are the answers.

First of all, LASIK eye surgery is a laser procedure with two parts. First we have to make a thin flap from the top part of the cornea, basically a thin hinged layer we can temporarily fold to the side (painlessly!).

Next we use an ‘excimer‘ laser to reshape the exposed cornea to correct the vision focusing problem. The laser will polish away certain areas, depending on your prescription, to bring back clear vision.

The flap is put back in place and heals over very quickly. The eye feels gritty or scratchy for about 3-4 hours only. OK, so far so good.

For the first stage, making a flap, we have used a mechanical device called a keratome (or microkeratome). Keratomes have been around for 50 years and use a blade to make a controlled cut. This stage is where significant complications can occur, so we have been looking for a way to make this corneal flap but without the need for a blade.

Along come femtosecond lasers.

The eye lasers use ultra-short infra-red low energy pulses to create microscopic bubbles at a precise depth below the surface of the cornea. If you do this millions of times, you can create a super precise separation as a sheet, and hence a near-perfect corneal flap, which you can now fold to the side ready for vision correction with a second laser.

The femtosecond laser means we no longer run risks from using a blade to cut a flap. This means safer LASIK eye surgery.

You can watch a video of femtosecond laser eye surgery here.

More on femtosecond lasers coming soon.

Definition for femtosecond:

(This definition follows U.S. usage in which a billion is a thousand million and a trillion is a 1 followed by 12 zeros.)

A femtosecond is one millionth of a nanosecond or 10^-15 of a second and is a measurement sometimes used in laser technology. So that’s one billionth of a millionth of a second! As a comparison, one femtosecond to a second is like one second to 32 million years.

For comparison, a millisecond (ms or msec) is one thousandth of a second and is commonly used in measuring the time to read to or write from a CD-ROM player.

A microsecond (µs) is one millionth (10^-6) of a second.

A nanosecond (ns or nsec) is one billionth (10^-9) of a second and is a common measurement of read or write access time to random access memory. A picosecond is one trillionth (10^-12) of a second, or one millionth of a microsecond. An attosecond is one quintillionth (10^-18) of a second and is a term used in photon research.

[tags] LASIK, femtosecond, laser eye surgery, safety, risks, compications [/tags]

 We have been using the Ziemer LDV for 3 weeks now with great results. Vision results and flap creation have been excellent and without any complications.

For eyes with pre-existing corneal scars there has always been a question mark over the ability of femtosecond lasers to create LASIK flaps as the scar tissue may prevent the laser from passing through the tissue. Intralase users report that they found an inability perform LASIK to treat eyes that have pre-existing moderate to dense corneal scars.

Unlike the Intralase (American made femtosecond eye laser), the Swiss-made LDV will pass through even fairly dense corneal scars without a problem. So far the LDV has created excellent flaps in these cases. I will keep you updated on our progress.

[tags] laser eye surgery, complications, femtosecond, flap, Intralase, LASIK, risks, safety, Z-LASIK, Ziemer [/tags]